1. Field of the Invention
This invention relates to the treatment of waste materials and in particular, the compaction of solids by removing water.
2. Prior Art
The use of augers as a means of transporting material in a conveyor like manner is well known and established in a variety of different configurations.
U.S. Pat. Nos. 1,906,395 and 5,000,307 are representative. Additionally, implementation of auger lift systems for handling waste material during the treatment of sewage is well known and established. The JWCE Auger Monster™ series provides a modular headworks system where the auger is placed immediately downstream of a grinding unit to convey ground coarse solids out of the fluid stream for disposal in landfills and the like. In general, such auger systems are used to lift solids from a collection point in the fluid stream to a discharge point for removal from the system.
Given the inherent compaction that results by using a helical member, solid material is compacted to some degree while waste water entrained within the solids is separated, drained from the system and returned to the waste water stream. The dewatered coarse solids are preferred for disposal since the water content is reduced. These techniques thus essentially use the auger as a means to move, generally lift the sludge from one location to a higher, second location for removal while compaction is a secondary function, performed inherently by the auger.
Within such systems, the water content is significant and adds excess weight to the solid material that is to be removed. Consequently, there is a standing requirement to dewater, that is remove excess water from the system while still providing for the removal of solid material in a compacted form.
In such systems, while the auger provides a degree of compaction, if the solid material becomes excessively dense, that is compacted too much, then friction between the solid material mass entrained within the auger and the inside of the casing becomes to great, resulting in binding. The potential results include damage to the auger and/or burning out the drive motor. Conversely, if the extent of compaction of the solid material is insufficient, then unnecessary water is carried along through the system resulting in decreased efficiency, higher cost for solid disposal and the like.